Battery listener for download service in native code.

components/download/internal/scheduler/battery_listener_unittest.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/download/internal/scheduler/battery_listener.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/test/power_monitor_test_base.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace download {
+
+using BatteryRequirements = SchedulingParams::BatteryRequirements;
+
+class MockObserver : public BatteryListener::Observer {
+ public:
+  MOCK_METHOD1(OnBatteryChange, void(SchedulingParams::BatteryRequirements));
+};
+
+class BatteryListenerTest : public testing::Test {
+ public:
+  BatteryListenerTest() {}
+  ~BatteryListenerTest() override = default;
+
+  void CallBatteryChange(bool on_battery_power) {
+    DCHECK(listener_);
+    static_cast<base::PowerObserver*>(listener_.get())
+        ->OnPowerStateChange(on_battery_power);
+  }
+
+  void SetUp() override {
+    power_monitor_ = base::MakeUnique<base::PowerMonitor>(
+        base::MakeUnique<base::PowerMonitorTestSource>());
+
+    observer_ = base::MakeUnique<MockObserver>();
+    listener_ = base::MakeUnique<BatteryListener>();
+    listener_->AddObserver(observer_.get());
+  }
+
+  void TearDown() override {
+    listener_.reset();
+    observer_.reset();
+  }
+
+  std::unique_ptr<BatteryListener> listener_;
+  std::unique_ptr<MockObserver> observer_;
+
+  base::MessageLoop message_loop_;
+  std::unique_ptr<base::PowerMonitor> power_monitor_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BatteryListenerTest);
+};
+
+// Ensures observer methods are corrected called.
+TEST_F(BatteryListenerTest, NotifyObservers) {
+  listener_->Start();
+  EXPECT_CALL(*observer_.get(),
+              OnBatteryChange(BatteryRequirements::BATTERY_INSENSITIVE))
+      .RetiresOnSaturation();
+  CallBatteryChange(true);
+
+  EXPECT_CALL(*observer_.get(),
+              OnBatteryChange(BatteryRequirements::BATTERY_SENSITIVE))
+      .RetiresOnSaturation();
+  CallBatteryChange(false);
+  listener_->Stop();
+};
+
+}  // namespace download